Hardness tester



FIG. 1 is a front, right-side, top perspective view of the hardness tester;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a right-side elevational view thereof;

FIG. 5 is a left-side elevational view thereof;

FIG. 6 is a rear elevational view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is an enlarged view of the area bounded by arrow 8′ and 8″ in FIG. 4.

The broken lines depict unclaimed parts of the hardness tester, and thus form no part of the claimed design. The dot-dot-dash chain lines depict boundaries of the enlarged area, and thus form no part of the claimed design. 

CLAIM The ornamental design for a hardness tester, as shown and described. 